Anti-inflammatory, but not lipid-lowering, activity of hepatocyte PPARα improves atherosclerosis in Ldlr-deficient mice
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE295990 | GEO | 2025/05/28
REPOSITORIES: GEO
Similar Datasets
Project description:Autophagy is an evolutionally conserved catabolic process that recycles nutrients upon starvation and maintains cellular energy homeostasis1-3. Its acute regulation by nutrient sensing signaling pathways is well described, but its longer-term transcriptional regulation is not. The nuclear receptors PPARα and FXR are activated in the fasted or fed liver, respectively4,5. Here we show that both regulate hepatic autophagy. Pharmacologic activation of PPARα reverses the normal suppression of autophagy in the fed state, inducing autophagic lipid degradation, or lipophagy. This response is lost in PPARα knockout (PPARα-/-) mice, which are partially defective in the induction of autophagy by fasting. Pharmacologic activation of the bile acid receptor FXR strongly suppresses the induction of autophagy in the fasting state, and this response is absent in FXR knockout (FXR-/-) mice, which show a partial defect in suppression of hepatic autophagy in the fed state. PPARα and FXR compete for binding to shared sites in autophagic gene promoters, with opposite transcriptional outputs. These results reveal complementary, interlocking mechanisms for regulation of autophagy by nutrient status. Mouse liver PPARα cistromes in fed 8-week-old male WT or PPARα KO mice treated with or without its synthetic agonist ligand GW7647twice a day were generated by deep sequencing in quadruplicate using illumina
2014-09-27 | E-GEOD-61817 | biostudies-arrayexpress
Project description:Nonalcoholic fatty liver disease (NAFLD) is associated with an increased risk of cardiovascular disease (CVD). Liver is the major source of the circulatory proteins and alterations in plasma proteome have been implicated in atherosclerosis. We used a recently developed 2H2O-metabolic labeling method in combination with the label-free quantification to evaluate the effect of a Western diet (WD) on the dynamics of plasma proteins in LDL receptor-deficient (LDLR-/-) mice, a model of NAFLD and atherosclerosis. There were no significant changes in the expression level of total proteins due to the WD with a bulk protein mean half-life of 18.0±15.1 hours in control and 16.7±11.1 hours in WD groups. WD led to pro-inflammatory distribution of circulatory proteins analyzed in apoB-depleted plasma attributed to their increased production. The fractional catabolic rates of fast-turnover proteins with stress-response, lipid metabolism and transport functions were significantly increased with WD (P<0.05). The pathway analyses revealed that alterations in plasma proteome dynamics were related to the suppression of hepatic PPARα, which was confirmed based on reduced gene and protein expression of PPARα on WD. These changes were associated with ~4 fold increase (P<0.0001) in pro-inflammatory property of apoB-depleted plasma. In conclusion, the proteome dynamics method reveals pro-inflammatory remodeling of plasma proteome relevant to liver disease. As in vivo metrics of liver function, this approach can be used to test therapies in NAFLD and other diseases
2016-06-06 | PXD004270 | Pride
Project description:Genome-wide association studies (GWAS) have identified hundreds of susceptibility loci for chronic and inflammatory disease phenotypes in humans. There is increasing evidence that chronic inflammation is a crucial driver in the pathogenesis of cardiovascular diseases (CVD), which may be genetically determined. To understand the genetic architecture underlying chronic inflammation and CVD we performed a systematic analysis of (1) common risk alleles coming from published GWAS, (2) of protein-protein interaction (PPI) networks informed by (3) gene expression data with a defined molecular target involved in the inflammatory processes promoting CVD, MRP8. (4) through analysis of integrated haplotype scores (iHS) and FST values in HapMap phase 2 data, we investigated whether recent selection pressure acting upon inflammatory genes affected CVD susceptibility loci. Our findings provide significant evidence for a PPI network, which connects inflammatory and cardiovascular susceptibility genes, and establish a genetic framework of inflammatory CVD. 41.59% of PPI genes are associated with immune functions. 28.3% of integrated genes can be linked to both, an inflammatory and cardiovascular disease phenotype. Interestingly, CDKN2B, and CELSR2/PSRC1/MYBPHL/SORT1, unequivocally replicated CVD loci, are integrated within this network as are several SNPs located in transcription factor recognition sequences, i.e. NFKB1, STAT3, which are key factors in inflammation. Finally, we observed a significant enrichment of inflammatory variants within CVD cluster loci that are targets of selection. Overall, 32 genes exhibit traces of selection, 16 of which are part of the PPI, further suggesting that recent selective sweeps may have affected the genomic architecture underlying CVD. 6 samples, no replicates.
2015-09-01 | E-GEOD-54989 | biostudies-arrayexpress
Project description:Peroxisome Proliferator-Activated receptor α (PPARα) and cAMP-Responsive Element Binding Protein 3-Like 3 (CREB3L3) are transcription factors involved in the regulation of lipid metabolism in the liver. The aim of the present study was to characterize the interrelationship between PPARα and CREB3L3 in regulating hepatic gene expression. Male wildtype, PPARα-/-, CREB3L3-/- and combined PPARα/CREB3L3-/- mice were subjected to a 16-hour fast or 4 days of ketogenic diet. Whole genome expression analysis was performed on liver samples. Under conditions of overnight fasting, the effects of PPARα ablation and CREB3L3 ablation on plasma triglyceride, plasma β-hydroxybutyrate, and hepatic gene expression were largely disparate, and showed only limited interdependence. Gene and pathway analysis underscored the importance of CREB3L3 in regulating (apo)lipoprotein metabolism, and of PPARα as master regulator of intracellular lipid metabolism. A small number of genes, including Fgf21 and Mfsd2a, were under dual control of PPARα and CREB3L3. By contrast, a strong interaction between PPARα and CREB3L3 ablation was observed during ketogenic diet feeding. Specifically, the pronounced effects of CREB3L3 ablation on liver damage and hepatic gene expression during ketogenic diet were almost completely abolished by the simultaneous ablation of PPARα. Loss of CREB3L3 influenced PPARα signalling in two major ways. Firstly, it reduced expression of PPARα and its target genes involved in fatty acid oxidation and ketogenesis. In stark contrast, the hepatoproliferative function of PPARα was markedly activated by loss of CREB3L3. These data indicate that CREB3L3 ablation uncouples the hepatoproliferative and lipid metabolic effects of PPARα. Overall, except for the shared regulation of a very limited number of genes, the roles of PPARα and CREB3L3 in hepatic lipid metabolism are clearly distinct and are highly dependent on dietary status.
2019-01-23 | GSE121096 | GEO
Project description:Anti-inflammatory, but not lipid-lowering, activity of hepatocyte PPARα improves atherosclerosis in Ldlr-deficient mice
| PRJNA1259018 | ENA
Project description:Patients with non-alcoholic fatty liver disease (NAFLD), especially advanced non-alcoholic steatohepatitis (NASH), have an increased risk of cardiovascular diseases (CVD) due to the production of pro-inflammatory factors, vasoactive and thrombogenic molecules, or insulin resistance and related disorders. While elevated risk and incidence of CVD events in NAFLD/NASH are well established, whether such events will, in turn, influence the pathogenesis of NAFLD remains unknown. Here, we show that myocardial infarction (MI) accelerates the linear hepatic pathological progression of NAFLD. In humans, NAFLD patients who experienced CVD events after their diagnosis of NAFLD show a rapid progression of hepatic fibrosis. In mouse models of NASH, MI promotes hepatic fibrosis, accompanied by elevated circulating Ly6Chi monocytes and their recruitment to the damaged liver tissues. Depleting these cells abrogate MI-induced hepatic pathological effects in mice with NASH. Meanwhile, MI substantially elevates circulating and cardiac periostin contents, which act on hepatocytes and stellate cells to promote hepatic lipid accumulation and fibrosis, finally exacerbating hepatic pathological progression of NASH. Additionally, specific silence of cardiac periostin markedly attenuates MI-induced hepatic pathological progression of mice with NASH. These preclinical and clinical results demonstrate that MI alternates systemic homeostasis and upregulates the production of pro-fibrotic factors, triggering cross-disease communication that accelerates hepatic pathological progression of NAFLD.
2024-06-04 | GSE254698 | GEO
Project description:Autophagy is an evolutionally conserved catabolic process that recycles nutrients upon starvation and maintains cellular energy homeostasis1-3. Its acute regulation by nutrient sensing signaling pathways is well described, but its longer-term transcriptional regulation is not. The nuclear receptors PPARα and FXR are activated in the fasted or fed liver, respectively4,5. Here we show that both regulate hepatic autophagy. Pharmacologic activation of PPARα reverses the normal suppression of autophagy in the fed state, inducing autophagic lipid degradation, or lipophagy. This response is lost in PPARα knockout (PPARα-/-) mice, which are partially defective in the induction of autophagy by fasting. Pharmacologic activation of the bile acid receptor FXR strongly suppresses the induction of autophagy in the fasting state, and this response is absent in FXR knockout (FXR-/-) mice, which show a partial defect in suppression of hepatic autophagy in the fed state. PPARα and FXR compete for binding to shared sites in autophagic gene promoters, with opposite transcriptional outputs. These results reveal complementary, interlocking mechanisms for regulation of autophagy by nutrient status.
2014-09-27 | GSE61817 | GEO
Project description:<p>Despite intensive research and constant medical progress, sepsis remains one of the most urgent unmet medical needs of today. Most studies have been focused on the inflammatory component of the disease, however, recent advances support the notion that sepsis is accompanied by extensive metabolic perturbations. During times of limited caloric intake and high energy needs, the liver acts as the central metabolic hub in which PPARα is crucial to coordinate the breakdown of fatty acids. The role of hepatic PPARα in liver dysfunction during sepsis has hardly been explored. We demonstrate that sepsis leads to a starvation response that is hindered by the rapid decline of hepatic PPARα levels, causing excess free fatty acids, leading to lipotoxicity, and glycerol. In addition, treatment of mice with the PPARα agonist pemafibrate protects against bacterial sepsis by improving hepatic PPARα function, reducing lipotoxicity and tissue damage. Since lipolysis is also increased in sepsis patients and pemafibrate protects after the onset of sepsis, these findings may point towards new therapeutic leads in sepsis. </p>
2020-01-10 | MTBLS1386 | MetaboLights
Project description:Previously published results from our double-blind, placebo-controlled parallel study with docosahexaenoic acid (DHA) supplementation (3 g/d, 90 d) to hypertriglyceridemic men (39-66yr) showed that DHA reduced several risk factors for cardiovascular disease (CVD), including the plasma concentration of inflammatory markers. To determine the effect of DHA supplementation on the global gene expression pattern, we performed Affymetrix GeneChip microarray analysis of blood cells (treated with lipopolysaccharide (LPS) or vehicle) drawn before and after the supplementation from the hyperlipidemic men who participated in the previous study. Genes that were significantly differentially regulated by the LPS treatment and DHA supplementation were identified. Differential regulation of 18 genes was then confirmed by quantitative RT-PCR. Both microarray and qRT-PCR data showed that the expression of LDL receptor (LDLR), oxidized LDL receptor (OLR1), and cathepsin L1 (CTSL) was significantly suppressed by DHA supplementation; however, LPS stimulated the expression of LDLR and CTSL but not that of OLR1. LPS up-regulated and DHA suppressed the expression of prostaglandin E synthase (PTGES), PPAR delta, and various chemokines. Enrichment with Gene Ontology categories demonstrated that the genes related to transcription factor activity, immune responses, host defense responses, inflammatory responses, and apoptosis were inversely regulated by LPS and DHA. These results provide supporting evidence for the anti-inflammatory effects of DHA supplementation, and reveal previously unrecognized genes that are regulated by DHA, and are associated with risk factors of cardiovascular diseases. Double-blind, placebo-controlled parallel study with DHA supplementation to hypertriglyceridemic men. Gene expression detected in LPS-stimulated (LPS) and unstimulated (vehicle) white blood cells. 3-4 replicates per group.
2010-02-21 | E-GEOD-20114 | biostudies-arrayexpress
Project description:Hepatic PPARα dysfunction in porcine sepsis
| PRJNA904738 | ENA